Materials and construction methods for production of singly ply membrane roofing materials are varied but generally consist of a top ply and bottom ply thermoplastic membrane surrounding a structural scrim. Often used in “glue down” applications a needlefelt or fleece nonwoven is added to the backside of the bottom membrane to enhance the ability of the membrane composite to stick to the roof deck of the structure and provide a barrier between the glue and membrane. There is a need to have single ply roofing membrane that forms a char barrier often in wood decking flat roof structure during a fire event. Additionally, it has been discovered that adding additional non-charring FR materials significantly improves the FR performance of the composite.